1. Field
The following description relates to a composition for preventing or treating brain diseases or diabetes, and more specifically, a pharmaceutical composition or a food composition for preventing or treating degenerative brain diseases or diabetes containing a compound for downregulating expression of BACE1 proteins. The following description also relates to a method for preventing or treating a degenerative brain disease or diabetes, comprising administering a pharmaceutical composition to a subject in need thereof, wherein the pharmaceutical composition decreases expression of BACE1 proteins.
2. Description of Related Art
In the United States, Alzheimer's dementia (Alzheimer's disease) has a prevalence of about 3% in people aged 65 to 74, about 19% in people aged 75 to 84, and about 50% in people aged 85 or over. In Korea, according to a recent report focusing on rural areas, symptoms of dementia has a prevalence of about 21% in people aged 60 or over, and 63% of those have Alzheimer's dementia.
Such Alzheimer's dementia is a disease accounting for 50 to 70% of dementia, which causes gradual degeneration of nerve cells and loss of cognitive ability. Alzheimer's dementia may be classified as familial Alzheimer's dementia, due to genetic factors, or sporadic Alzheimer's dementia, of which causes are not accurately known and which occurs in a great number of patients. Alzheimer's dementia patients may show a memory loss and psychological symptoms such as mental abnormality including increased anxiety and a hypersensitivity reaction, which results in a complex cognitive defect. In the brains of patients who have died of Alzheimer's dementia, pathological evidence of senile plaque and neurofibrillary tangles may be visible. According to present understanding, senile plaque is formed by extracellular accumulation of proteins, dead cells, and the like. A main component thereof is amyloid beta peptides (Aβ) (Hardy, J. et al, Nat. Neurosci. 1:355-358, 1998).
A gradual loss of a cognitive reaction, which is a main feature of Alzheimer's dementia patients, is caused by abnormally accumulated Aβ. Aβ deposited in the brains of Alzheimer's dementia patients is generated from amyloid precursor proteins (APPs) through a proteolysis process. An APP is decomposed by beta-secretase (BACE1) and gamma-secretase (γ-secretase), and Aβ is generated (Craven, R., Nat. Rev. Neurosci. 2: 533, 2001; Small, D. H. et al., Nat. Rev. Neurosci. 2: 595-598, 2001; Yankner, B. A., Neuron 16: 921-932, 1996; Selkoe, D. J., Nature 399: A23-A31, 1999).
Accordingly, a substance for decreasing expression of beta-site APP-cleaving enzyme 1 (BACE1) that generates Aβ causing Alzheimer's dementia disease may be used as an agent for preventing and treating Alzheimer's dementia.